Duluth weather by month
Duluth runs from about -7°C in January to 21°C in July, with June the wettest month at 187 mm.
warmest month
July
21°C
coolest month
January
-7°C
wettest month
June
187 mm
worst air month
July
18 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -7°C | 11 mm | 145 h | 4 |
| February | -2°C | 12 mm | 218 h | 6 |
| March | 0°C | 65 mm | 258 h | 7 |
| April | 5°C | 64 mm | 253 h | 5 |
| May | 12°C | 124 mm | 311 h | 6 |
| June | 17°C | 187 mm | 315 h | 6 |
| July | 21°C | 72 mm | 413 h | 18 |
| August | 20°C | 68 mm | 328 h | 13 |
| September | 19°C | 25 mm | 346 h | 7 |
| October | 12°C | 48 mm | 252 h | 4 |
| November | 3°C | 71 mm | 130 h | 3 |
| December | -6°C | 46 mm | 85 h | 4 |
About 3,054 hours of sun a year. Roughly 80 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-27. Full method, licences and the list of sources we rejected are on the methodology page.